Clutch for ironing machine mechanism



Oct.25;1938. w 2,-134,-202 7' CLUTCH FOR IRONING MACHINE MECHANISM Filed 001;. 15, 1936 C 2 Sheejc-Sheet' 1 INVENTOR John WRackx BY v at. Tog

Oct. '25, 1938,

J. w. RACKLY'EFT CLUTCH FOR IRONING MACHINE MECHANISM Filed OCt- 15, 1936 2 Sheets-Sheet 2 INVENTOR John W Rackl ATTORQ' vision of a friction clutch which issubstantially close-fitting tolerances.

' Patented ocezs, 1938 cLU'ron ron mo MECHANISM- John W. Racklyeft, Cleveland, Ohio, assignor to The Apex Electrical Manufacturing Company, Cleveland, 0hio,a corporation of .Ohio

t n O ber is, mast-ha; No. 05.111

- u-oisim (c1. 192-'-26) This invention relates to clutches and it constitutes a continuation-in-part of the invention disclosed inmy copending application Serial No. 135,040 which was filed July 13, 1934 for Ironing machine mechanism.

The present invention has for its objects the provision of a simple and inexpensive, easily controlled form of friction clutch construction which is adapted to provide a positive driving connection when its cooperating driving and driven parts are in engagement with each other, such parts being adapted to be substantially free or each other when the clutch is adjusted to its disengaged position.

Other objects of the invention include the pronoiseless and positive in its operation and which utilizes an expansible member adapted to be driven by a clutch spool and arranged for meeting driving engagement with a similar clutch SPOOL. I 1,

Another object of the invention relates to the provision of aclutch which is capable of driving relatively heavy loads and in which the engagement and disengagement of the clutch may be controlled by the exertion of a very slight effort on the part of the operator. a 1

Another object of the invention relates to the provision of a clutch having a minimum number of moving parts whereby excessive wear of, the clutch is avoided. 3

Another object-or the invention relates to the provision of a clutch in which the parts are arranged and constructed so that they are relatively easy to manufacture and do not require Another object of the invention relates to the provision of aclutch of simple and inexpensive construction which may be subjected to considerable use Without appreciable wear on the operat-, ing parts of the clutch.

' p -A further object of theinventionrelates to the provision of a clutch in which the clutch parts occupy a relatively small space and'are-arranged so that the clutch may be readily assembled and vdisassembled.

These and other objects of the invention will become more apparent and better understood after consideration has been given tothe following detailed description of the invention taken in connection withthe drawings which show, merely by way of illustration, structure adapted for carrying out the objects of the invention ,Stated in general terms, this invention comprehends the provision of a clutch employing a helical frictionmemberlwhich is adaptedto connect and disconnect the driving and driven parts or the clutch; Aportion of the length or the'helical member or a separate spring is usedt'o' insurethe complete release of the, clutch when it is'disengaged and-a continuously acting friction drag is provided to. insure instantaneous and positive action of the clutchwhen it is adjusted to it's engagedposition. In the drawings,- Figurel'i's a side elevational view of an ironing machine illustrativeof on'eembodiment of the invention; Figure 2is an enlargedsec'tional view takenon' line 2-;2, Figure 1, illustrating some of the mechanical details or the machine shownjin Figure 1; Figures 3, 4,- 5 and;6 are detail sectional views taken onlineS 8-4, l'- -l, l-iand of Fig ure 2.respectively; Figure '7 is an enlarged detail sectional view taken on line 'I'-'|, Figure 2; Figure 8 is an enlarged detail 'sectional vtew taken on line 8- 8,Figure'2; Figure 9 is an enlarged detail plan view of a modified form of clutch which may be used in place of'thejclutch shown in'Fig-' ure 8; Figure 10 is a sectional view takenon line l0l0, Figure9i Figure 11 is a detail side elevational view ofapdrtion of the structure shown in Figure. 9; Figure 12 is a detail side elevational view taken on line, I is aldetail side elevational view of a modified form of clutch control; Figure 14 is a'plan view ota combined control and drag plate which is used in connection with'the device shown in Figure13; andFigure 15 is a" detail sectional view.

taken on line l5.-|5, Figure 8. g Referring now to Figural, the ironing machine selected for the purpose of illustrating the details of this invention comprises a supporting structure I for carrying a padded rotatable ,roll 2 and. a heated ironer shoe 3 which latter two. members constitute the ironing elements of the machine, one of which is arranged tor. relative movement with respect to the other,- so that the maybe moved into and out of shoe and the roll pressing contact with each other at the, wine: the operator- The ironer shoe is carried onv the'upper end of an arm 4 having associated therewith at its lower end, a supporting bracket. 5 carried by the supporting structure lot the machine.- Mean'sf' including a rod 42 housed within the-tube 8 and a control lever having a handle I, are provided for manually shifting the shoe into and out-of engagement with the roll and such means consti-' tute a safety release'for-releasing the' shoe from pressing engagement'with the roll.

Suitable operating mechanism is housed with- 5 Ila-l2, Figure 10; Figure 13' tip control.

.outer' 'en'd of the roll.

trol is arranged to be operated by a very light' pressure and may be aptly described as a finger- A second lever I 2, located the rotation of the roll at such times when it is intended for using the machine for pressing operations, in which case, the manipulation of the lever H serves only to shift the roll into and out of engagement with theshoe and does not cause the rotation of the roll as is done in the ordinary operation and use of the machine.

Referring 'now to the sectional view of Figure 2 and the'detail views 3, 4, 5 and 6, it will be seen that the roll of the machine is supported entirely from the gear case 8, which has an upper compartment [3 for most of the operating mechanism of the machine. A removable cover plate I4 is provided to permit access. to the operating elements housed within the compartment l3. 'The gearcase 8 has a laterally extending hole low boss l5 in which is rigidly fitted a tube l6, provided with a bracket 23 for rotatablysupporting the outer end of a rocker-shaft 22 which supports angupstandi'ng bearingmember IT for the Theinner "end of the roll is carried on a bearingmember I 8 fixed to a bracket 20 rigidly securedby meansof a pin 2| to'the rocker-shaft 22, which extends the length of the roll in a position a slight distance below the tube l6. The bearing member I! hasa reduced, laterallyoifsetpart 26 at itsupper end which is 'received'in a tubular bearing member 21, fixedly carried by the end-cap 28 of the roll 2. The roll is held against axial movement with respect to its supporting" bearings by means of a bolt 30 and an associated washer 3| which cooperate with the roll end cap 28 and the bearing member I! to hold the roll in proper position with respect to its bearings. The bearing member I 8 engages with a bearing surface 32 provided by a lateral annular extension formed integrally with an internal gear 33 which may conveniently be formed from a single die-casting. The gear 33 may have a pressed fit in the end of' the roll, or it may be fixedlysecured atthis point by any suitable means such as screws or pins 34.

The roll supporting bearings are carried by the rocker-shaft 22 from a pointsome distance.

belowthe roll axis so that when this shaft is rocked by means which will be described in detail presently, the roll maybe shifted into and out of contact with the shoe 3 when the shaft 22 is rocked in one direction or the other. At the same timethis takes place, the internal gear 33 is brought into and out of meshing engagement with a gear or pinion 35 fixedly secured to a shaft 36 which is mounted for rotation about a fixed axis. V

The pinion 35 servesto drive the roll when the roll is movedlaterally into contact with the shoe and when the roll is moved out of contact with the shoe, the gears 33 and 35 are separated from meshing engagement with each other and the power drive of the roll is thus automatically conalongside the lever H on the gear case 8, is provided for preventing The outer cover of the roll 2 is in the form of one or more layers of suitable padding 3! and the shoe is provided with a heating element 38 which may for convenience be a resistance-wire heating element whichis'operated from the same source of electrical current supply as is the driving motor ID of the machine. A suitable heat insulating cover 40 is provided at the rear of the heating element-38m prevent the rear side of the shoe 3 from becoming excessively hot and also for the purpose of .increasing the transfer 01' heatto the forward or working face of the shoe. Referring nowpa'rticularly to Figures 2 and 8 and some of the detail views, it will be seen that the gear case '8 has a hollow laterally extending boss-5| provided for reception of a tubular hearing member or sleeve 52 which is pressed into the boss 5| so-as to form a' rigid and fixed part of the gear case. The outer and inner surfaces of the sleeve 52 are smoothly finished to provide bearing surfaces for the parts which will be de-' scribed presently. The gear 35 is fixed to one end of the shaft 36and atits other end a cylindrical driven member 53 'is secured to the shaft by means of a pin 54. The pin 54 is secured to oneend of a coil spring friction clutch member 55, and as is best shown in Figure 8, the spring 55 comprises a number of turns which are wrapped about the member 53'and' an adjacent sleeve-56"which'is fixed to a worm gear 51, driven by a worm 56 carried ona shaft 60. A bearing6l for one end of the shaft 60 as'is shownin Figure 2 is formed in a boss 62 carried at one sideof the gear case and the other end of the shaft 60 is mounted in a bearing 63 provided by the boss 64. also formed integrally with the gear case." I

At the outermost end of the shaft 60 there is fixed a belt pulley 65 for receiving a belt 66 which in turn is engaged by a belt pulley'61 carriedby spring is welded or'otherwise secured at 68 to one end of three or more turns of a larger spring 68 or non-clutching 'end portion which is wrapped about the end of the coil spring 55. The other end 10 (see Fig. 4) of the" spring 68 is-upturned so that it may be engaged by a stop 1| which may be moved into and out of the path of this end of the spring. r

The stop 1| is carried ona shaft 12, fixedly secured to the control lever I2, which is located exteriorly of the gear case 8. The lever l2 can bemoved to one orthe other of two limiting positions, as determined by a pair of spaced stops l3 and 14, formed exteriorly of the gear case and fixed thereto. When the lever occupies its upper position, as shown in Figure 1, the stop "II will be in the path of the end of the spring 68 and it will serve to hold the clutch spring 55 from driving engagement wlth'the sleeve 56. v

The shaft 36 which carries the rolldriving gear 35 is thus prevented from rotating'and with the control lever l2 in the stated position, the roll canbe moved into' and out of engagement with the shoe without effecting the rotation of the roll. Normally, however, the lever 12 is in its lower position in contact with the stop H, in which position, the clutch engaging stop H occupies a position outside the path of the end 10' of the clutch spring, so that the clutch spring is in continuous driving engagement with the sleeve 56.

Leakage of oil from the gear case is prevented by means of a suitable packing Washer 15 which is maintained in sealing relation around the shaft 12 by a spring 18 which is held against the packing washer 15 by a washer 11 secured in position on the rocker-shaft 12 by means of a pin 18. Viewed from the end of the machine at which the gear'case 8 is located, the worm gear i'l'rotates in a clockwise direction and the coils of the springs 55 and 68 are wound so that move ment in a counterclockwise direction on the end 10 of the spring 68 will tend to uncoil the springs 55 and 68. The spring 68 is provided for the purpose of preventing frictional drag between the clutch parts when they are in disengaged position and when the driving elements of the machine are in operation. 1

The manner in which this works 'isas follows: When the stop ll engages with the upturned end 10 of the spring 68, there is initially built up in the coils of this spring a certain amount of tension and when th s tension reaches a predetermined value it serves to disconnect the driving engagement of the spring 55 with the sleeve 56, and after this takes place the tension of the spring 68 then operates to completely release the spring 55 from the sleeve 56. i

This is accomplished by reason. of the fact that it takes a slightly greater force to effect the disengaging movement of the clutch than it does to hold the clutch parts in their disengaged position, which difference amounts to the difference between the static and kinetic friction of the driving and driven clutch parts; the static fric tion being of slightly greater value, as is customary, so that the aforesaid results may be accomplished.

As is best shown in Figure 8, the ,sleeve 56 extends outwardly a considerable distance from each side of the worm gear 51. The portion of the sleeve to the left of the worm gear is pro: vided for v selectively driving an eccentric 80. The eccentric is'mounted for rotation on the fixed bearing sleeve 52 which is carried by the boss 5| of the gear case. This eccentric may also be formed from a die-casting and it is provided at one edge with a flange 8| and opposite thereto it has an offset hub part 82 of substantially the same shape and dimensions as the adjacent part of the sleeve 56.

A number of teeth 83, as best shown in Figure 7, are provided on one side of the eccentric. The spaces between these teeth are providedfor receiving the end 84 of the clutch spring 85, which is provided foreffecting selective driving engagement between the sleeve 56 ofthe worm gear 51 and the eccentric 80.

The clutch spring 85 is of substantially the same construction as the clutch spring 55 and it is secured at one end to an end of an outer spring 86 having a number of turns terminating at its other end with an upturned part 81 (see Fig. 2) which engages with one or the other of a pair of stop arms 88 and 90 which are carried on a shaft 9!, which in turn is fixed for movement with the control lever H. The control lever H and the associated stops are normally maintained in position to engage the end 81 "f the clutch spring by means of a coil spring-62 which engages at one end with the shaft 9| and at its other. end with the gear case 8. As in the caseof the springs 55 and 66, the spring 86 forms anonclutching end portion for the clutch spring 85. 1

Packing means 16a similar to that described in connection with the rod- 12; are provided at the pointwherethe shaft .9! traverses the wall of the gearcase. A stop 93 is"-provlde d exterlorly of the gear case 8 to maintain the lever H in proper position against the tension of the spring 92. The stop arms 88 and 90 are spaced sub-l 'stantially 180 from each other so that the clutch formed in part by the spring 85', may bedisengaged after each successive half-tum,- provided the lever l'i isreleasedsoon-after ithas been depressed, which is the normal method of operating the machine; The adiustment'provide d by the teeth 83 permits the shifting of the spring to take care of slight irregularities as may occur between different clutch springs. The face of the eccentric 80 is engaged bya yoke 94 pivotally connectedat 95 to a crank arm 96 which is fixed to the rocker-shaft 22. When the clutch formed in part by the spring 65, is in driving engagement, the eccentric will be rotated approximately moving-from the full line to the dotted line position, as shown in Figure 5 or vice versa as the case may be, and this'movementof the eccentric serves -to rock the shaft 22 and in this manner swing thebearingmembers l1 and i8 toward'and away from the shoe of the ironer, thus bringing'the padded roll and the heated shoe into: and outof'pressing contact 'withleach other.

'"The rod 42 associated with the shoe 3,.is initially placed under some tension byi-the operation of the safety release when the shoe is moved to its operative position by the handle-'1. This may'be-readilyaccomplished by having the shoe supporting arm move into contact with a fixed stop( not'shown) as the shoe is movedto supporting arm 4 is fixed to the' torsion rod 42 as previously st'ated; arid this arm is free to move its operative position. The lower end ofthe shoe I about the axis ofthe rod 42 subject to the re-v straintoccasioned by the torsional effort of'such rod. 'When'thef'roll is moved into engagement with the shoe-there is considerable" pressure exerted between the contacting surfaces of the roll. and the shoe due both to the initial torsion in the rod and the added torsion in the rod caused by the contact pressure betwe'erithe roll andthe shoe. v

When the rollis shifted away from the shoe, the torsion of the spring rod '42 tends to speed the movement of the roll away from the shoe during the initial part of such movenientQand there ls-a strong tendency for the roll shifting eccentric toover-run the driving mechanism, causing the machine to be noisy and jerky in operationt In the present construction-a cam surface (see Figs. 5 and 7) is formed on one side of the eccentric member for the purpose of quietingv the operation of the machine. This surface is arranged so that when the roll is movedaway from -the shoe, the cam surface comes into engagement with a brake member'il'l. which is urged-against-v the cam face by means of.a spring 99,1pressing against a washer. illll, fixed on a pin I02, which transfers the tensionof the spring to thelbrake member 91, so that considerable pressure is exerted between the cam face 68 and the brake nected to the control lever l2.

member 61- when they move into engagement with each other. r g

In the modified form of clutch construction shown in Figures 9 to 12, thespring 68 associated with the clutch spring 55 andthe spring 56 associated with the clutch spring 85 are dispensed with and a diiierent arrangement which operates in substantially the same manner is substituted for accomplishing the result which is accomplished with the springs 68 and 86. 2 Many of the elements shown in Figures 9 to 12 are substantially or iden-.

tically the same as the correspondingly numbered elements previously described.

In the modified form of clutch construction, a

worm gear 51a fixed to a sleeve 56 constitutes the driving part of the clutch. The sides of this gear are grooved for receiving annular dragor clutch-energizer springs Ill) and III. The drag spring IIII irictionally engages with the gear 51a and at its end I I2 it is attached to an offset part I I3 of a drag ,or clutch-energizer plate I I5 which is notched for snugly receiving the end I I6 of the clutch spring 55a.

' 55a which end is rather closely .ilttedinto an aperture of the drag plate 5, as shown best in Figure ,9. The control plate Ill and the drag plate 5 are operatively connected to each other by means of a coil spring I22, one end of which is connected to the part I23 oi. the control plate and the other end of which is connected to the part I24 of the drag plate. I

The driving and driven parts of the mechanism illustrated in Figures and lime adapted to rotate in a clockwise direction. When the stop Ila is moved into engagementwith one or the other of the arms 8 and I20, the spring I22 begins to exert a pull upon the drag plate 5, and when this pull is suilicient to overcome the frictional engagement of the spring 55a with the driving clutch sleeve 56, the clutch will become disengaged and the extra pull of the spring I22, which is necessary to effect the initialdisengaging operation of the clutch, will be utilized in further uncoiling the clutch spring 55a to completely disengage it from the driving sleeve 56 and thus stop the operation or the gear 35.

In the event that the tension of ,the spring I22 is not sufll'cient to eiiect the disengagement of the clutch spring 55a, positive disengagement or the clutch spring will be effected when the end part llt'ofthe spring 55a contacts'with the end portion. o;t the notch I2I, which ordinarily loosely receives this end'of the clutch spring.

.The control for the clutch of the eccentric 86 is substantially the same and it operates in an identical manner to the clutch just described.

The eccentric clutch control includes a drag or clutch-energizer plate I25 and a controlplate a lip-haying stop arms I21 and I28 which are adaptedmr engagement with the stops 88 and SII ofitl ie-cbhtrol which'is operated by the lever II.

"Ihe lutmand'control plates are connected to each" other by means of a coil spring I30 which operates in a manner similar to the spring I22.

drag plate I25 is apertured for closely reor one or the other of the members l46of the plate l25a.

ceiving the end I ll of the clutch'spring 65a and the control plate also is notched at I32 for loosely receiving this end of the clutch spring.

, Inbothiormsoi' the invention, the clutch release. operates in' substantially the same manner a by utilizing the tension of a resilient member to substantially effect complete disengagement of a friction clutch employing a helical spring which is adapted to wraparound a driving member in effecting the engagement of"the clutch. 10

When either one of the clutches just described in connection with Figures 9 to 12 is released for engagement, the associated drag spring work: ing through its drag plate, assists in tightly wrapping the clutch spring around the driving part 15 arrangement much the same as shown'in Figures 20 13 and 14 which will be described presently.

Figures 13 and 14 illustrate, a slightly modified form of the invention in which the control and drag or energizer platesused in connection with the device illustrated inlFigure's 9 to 12 are com- 35 bined in a singleplate and the special provisions for insuring complete release of the clutch are dispensed with in thelatter form of the invention.

The clutch structure illustrated in Figures 13 andla comprises a clutch sleeve 56, a worm gear 30 51a rigid therewith and a worm 58 for driving the worm gear 51a. 'A pair oi! helical clutch springs b and 8511 are associated with the clutch sleeve 56. A pair of drag or clutch energizer springs lit and III are in contact with a grooved as portion of the worm gearlla. The spring Ill engages with an oilset part Ilia of a plate Illa which is. rotatably mounted upon the sleeve 66 and the spring III engages with asimilarly.

iorm'ed part I43 formed on the plate .l25a which is rotatably mounted on the sleeve 56 at the side "of the gear 51a opposite to the plate Illa.

The foregoing elements are not greatly diil'er ent irom'the structure previously described in connection with the form of, clutch shown in 4 The operation or this clutch is not greatly diiferent from the clutches previously described. During the rotation of the structure shown in Figure 13, the disengagement of'one or the other of the clutches may be eiIected by moving a stop (not shown) into the path of one or the other of the members I and I42 of the plate Il5a I45 and When the movement of either one of the plates II5a or I25a is arrested, the free end of the corresponding clutch spring is held against rotation and thus unwound from the driving clutch sleeve 56. when one or the other of the plates is released for movement, its corresponding drag spring will tend to wrap the "associated clutch 7o spring around the driving sleeve 56and inthis manner effect the engagement of the clutch.

The arrangement Just described illustrates the manner in which the clutch-energizing device may be used without the clutch-releasing device 15 in' a simple form of clutch mechanism which may be used in many cases Where special provisions for insuring the complete release of the clutch are not necessary or desirable.

The foregoing description and the accompanying drawings to which it relates, describes what might be termed the preferred modes of practicing the invention. It is to be clearly'understood,

however, that the invention includes each and ited to the particular andspecific structureshown and described herein.

Having thus invention what I described my claim is:

1. A selectively disengageable friction clutch comprising driving" and driven parts, a coil spring fixedly secured-at one end to oneof said parts and tensioned so as to frictionally engage the other of said parts, andstop means for releasing said spring from such frictional engagement, the unsecured end of said spring having resilient means connected thereto and engaged and initially tensioned by said stop means as a step prior to efiecting any disengagement of the clutch.

2. A selectively disengageable friction clutch comprising driving and driven parts, a coil spring fixedly secured at one end to one of said parts and tensioned so as to'frictionally engage the other of said parts, and means engaging said spring for releasing such frictional engagement, said spring terminating at its other end'in one or more turns spaced at all times from said driving clutch part and arranged to be initially tensioned and then to effect disengagement of a effecting frictional driving connection between said elements, and control means for effecting the disengagement of said resilient means with respect to one of said elements, said control means operating to initially tension the outer of said springs as a step prior to disengaging the said resilient means from driving engagement with said driving element, such initial tension operating to effect substantially complete disengagement between said driving clutch element and said resilient means.

4. A friction clutch mechanism, having, in combination, a driving and a driven element, a

resilient member for effecting frictional drivingv connection between said elements having a nonclutching end portion adapted to be initially tensioned before disengagement of said resilient member with respect to one of said elements is effected, and means for initiallytensioning the end portion and then effecting the disengaging movement of said resilient member whereby to completely disengage the clutch and thereby substantially prevent friction between said member and said driving element and heating of the clutch when in its disengaged position.

5. A friction clutch comprising, a' driving member having a cylindrical friction face, a driven member coaxial with said driving member, a helical spring permanently attached at one end to said driven member and extending in coiled relation about the friction face of said driving member, a drag plate rotatably mounted on said driving member, a" drag spring attached I to said plate and frictionally contacting said 'driving' member, means for connecting the free end of said helical spring to said drag plate, a control tain' the helical clutch'spring free of thefriction 7 race of said driving member.

I .6, A friction clutch comprising, a driving mem ber having a cylindrical friction face, a driven member coaxial with said driving member, a

helical springper'manentlyattachedat one end' to said driven member and extending in coiled relation aboutjthe friction'face of said driving member, a drag plate rotatably mounted on said driving member, a circular drag spring attached to said plate and frictionally gripping said driving member, means for connecting one end of said helical spring to said drag plate, and means 'for preventing the rotation of said drag plate and thus disengaging the clutch, said drag plate when released for movement operating to assist in wrapping said helical spring about the friction face of said driving member.

7. A friction clutch comprising, a driving member having a cylindrical friction face, a driven member coaxial with said driving member,a

helical spring permanently attached at one end to said driven member and extending in coiled relation about the friction face of said driving member, a drag plate rotatably mounted on said driving member, friction means comprising an annular spring engaging said driving member for lightly connecting said plate to said driving member, means for connecting the free end of said helical springto said drag plate, and means for preventing the rotation of said drag plate for disengaging the clutch, said drag plate when released for movement operating to assist in wrapping said helical spring about the frictio face of said driving member. 8. A friction clutch comprising, a driving member having a cylindrical friction face, a driven member coaxial with said driving member, a helicalspring permanently attached at one end tosaid driven member and extending in coiled relation about the friction face of said driving member, a drag plate rotatablymounted on said driving member, a drag spring attached to said said helical spring to said drag plate, a control plate rotatably mounted on said driving member andhaving an apertured portion for loosely receiving the free end of said helical spring, a resilient means connecting said control plate to said drag plate, a stop on said control plate, and a member for engaging said stop and thus disengaging said clutch, the resilient connection between said control plate and said drag plate operating to maintain the helical clutch spring free of the friction'face of said drivingmember.

9. A friction clutch comprising, a driving mem ber having a cylindrical friction face, a driven member coaxial with said driving member, a helical spring permanently attached at one end to said driven member and extending in coiled relation about the friction face of said driving member, a drag plate rotatably mounted on said driving member, an annular drag spring attached at one end to said plate and frictionally contacting said driving member throughout the major portion of its length, means fo'rconnecting the free end of said-helical spring .to said drag plate, and means-including a resilient elecoiled relation about the friction face of said driving'member, a drag plate rotatably mounted on said driving member, an annular spring interposed between said drag plate and driving member, said spring having a fixed. connection withsaid drag plate and a frictional connection with said driving member, means for connecting the free end of said helical spring to said drag plate, and means for preventing the rotation of said drag plate and thus disengaging the clutch,

, said drag plate when released for movement operating to assist in wrapping said helical spring about the friction face of said driving member.

11. A friction clutch comprising, a driving member having a cylindrical friction face and an annular grooved portion, a driven member coaxial with said. driving member, a helical spring permanently attached at one end to said driven member andextending in coiled relation about thefriotion face of said driving member,

a drag plate rotatably mounted on said driving member, a stop for engaging the free end of said spring and thus disengaging the clutch, and friction means seated in the grooved portion of said driving member cooperating with said drag plate to wind said spring about said driving member when the spring is released by said stop.

JOHN .w. RACKLYEF'I". 

